Those totals seem ominous; 4.69 billion tons is a huge number, and a 13% increase is certainly worrisome.

But let’s put those figures in perspective, shall we? Since the Worldwatch folks certainly won’t bother doing so, it’s important to analyze and compare both the data themselves and the rate of increase within the larger picture of overall GHG emissions.

For starters, the 13% increase in agricultural GHGH emissions represents a comparison that spans more than 20 years. During that time period, the overall annual increase in yield for such key crops as corn (1.77%), wheat (0.52%, rice (0.92%) and soybeans (1.08%) also increased, as well. Extending those annual increases across the same time period, while overall agricultural GHG emissions rose 13%, global yields on corn increased 40%; wheat 11%; rice 22%; and soybeans 24%.

(By the way, overall agricultural productivity over the last 50 years is approaching an 80% increase, according to FAO, dwarfing the increase in GHG emissions during that same time period).

Thus, at the same time that anti-livestock groups are wringing their hands over agriculture’s contribution to global warming, productivity increases for key food crops greatly exceeded the amount of GHG emissions resulting from overall global farming activities.

In other words, although GHG emissions went up, the net contribution of agriculture per bushel of food produced decreased significantly.

That’s cause for celebration, not consternation.

The real source of the problem

Then there are the raw numbers themselves.

By comparison with the estimated 4.69 billion tons of GHG emissions attributed to agriculture, global CO₂ emissions from worldwide transportation activities totaled 6.76 billion tons in 2010, according to UN data. That’s a 44.4% greater source of emissions, even granting FAO its questionable calculations regarding the total GHG contributions of global agriculture.

Even more dramatic, total GHG emissions from power generation using fossil fuels in 2010 exceeded 12.4 billion tons, nearly triple the amount attributed to agriculture.

Combined, those two sectors—transportation and power generation—accounted for 19.2 billion tons of GHG emissions (measured in CO2 equivalents). And keep in mind that we can neither project continued annual yield increases, nor pretend that total food production can go anywhere but dramatically upwards in concert with population growth. Thus there are limited opportunities to significantly shift the calculus on agriculture’s contributions to GHG emissions.

Conversely, there are major opportunities to reduce the total GHG emissions in transportation and power generation, using renewable fuels, solar and wind energy and application of technology, such as fuel-efficient vehicles and “smart” electrical grids.

If Worldwatch and other groups with similar agenda really want to reduce GHG emissions, they’d be better off focusing on the transportation and energy sectors. Those two areas represent a more significant source of GHG emissions, and the potential for reductions in those areas is vastly more viable.

One additional note: Since livestock, the source of “enteric fermentation” and the subsequent production of methane gas get singled out as the largest culprit within agriculture, it’s important to note that there are other categories that would offer significant reduction in emissions, without impacting one of the world’s most critical food sources:

For example: In forestry, FAO estimated that total GHG emissions in 2010 from deforestation exceeded 2.63 billion tons, again a total that could (and should) be substantially reduced through the application of modern forestry management and more rigorous protection of existing rainforests from “slash-and-burn” practices.

And let’s not forget that if—as so many veggie fanatics propose—global agriculture were to shift dramatically from meat production to cultivation of grain and other edible crops to replace calories lost by eliminating animal foods (although much of the rangeland where cattle, sheep and goats currently graze is wholly unsuited for row crops), vast acreage now covered with carbon-sequestering forests would have to be mowed down and plowed up, further exacerbating the already significant issue of deforestation’s negative impact on GHG emissions.

So when Worldwatch and their ilk trot out what they hope people perceive as negative numbers on GHG emissions associated with animal agriculture, not only do those data need to be compared with other sources that are much greater, but they need to be considered in the context of the ongoing challenge to feed the billions of people alive on Earth today and the billions more to come in the next several decades.

As an indicator of where we need to focus in balancing food production and CO2 emissions, the 4.69 billion tons of GHG emissions attributed to livestock may not be what Mark Twain termed “a damn lie,” but it sure is a damn lousy statistic. □

The opinions expressed in this commentary are solely those of Dan Murphy, a veteran food-industry journalist and commentator.